Vemurafenib is primarily used in the treatment of metastatic or unresectable melanoma, specifically in patients whose tumors carry the BRAF V600E mutation. It works by inhibiting the activity of the mutated BRAF protein, which is involved in promoting cancer cell growth and division. By blocking this protein, the drug helps to slow down or stop the progression of the cancer. It is often administered orally and is typically part of a targeted therapy regimen. In some cases, vemurafenib may be combined with other treatments, such as MEK inhibitors, to enhance its effectiveness and reduce the risk of resistance. Regular monitoring is required during treatment to manage potential side effects, which can include skin reactions, joint pain, and photosensitivity.